The present invention relates to a method of manufacturing a semiconductor device, in particular, to a technology effective when applied to a method of manufacturing a semiconductor device including a step of forming element isolation regions.
Element isolation regions are formed by making trenches in a semiconductor substrate and then filling these trenches with an insulating film. A semiconductor device is manufactured by forming various semiconductor elements in active regions defined by these element isolation regions. Active regions can be electrically isolated from each other by these element isolation regions.
Japanese Patent Laid-Open No. 2006-173260 (Patent Document 1) describes a technology of neutralizing a semiconductor substrate before wet etching treatment.
Japanese Patent Laid-Open No. 2008-113028 (Patent Document 2) describes a technology of attaching a substance, which has a more positive potential than the standard electrode potential of hydrogen, to a portion of a silicon surface, causing an oxidation reaction between HF and the silicon at the portion of the silicon surface to which the substance has been attached to form electron e−, while blocking light to the silicon and thereby suppressing formation of an electron-hole pair in the silicon, and reacting the electron e− and a hydrogen ion H+.
The technology described in Japanese Patent Laid-Open No. 2009-49293 (Patent Document 3) has a step (a) of forming a first insulating film 11 on a substrate 12, a step (c) of selectively removing the first insulating film 11 by wet etching, and a step (d) of forming a second insulating film 17 on a region of the substrate 12 from which the first insulating film 11 has been removed. In the step (c), the surface of the substrate 12 is irradiated with illumination light of visible light or infrared light during at least a period from when wet etching is started until the substrate is brought into contact with a chemical solution (symbols used here correspond to those used in Patent Document 3).    [Patent Document 1] Japanese Patent Laid-Open No. 2006-173260    [Patent Document 2] Japanese Patent Laid-Open No. 2008-113028    [Patent Document 3] Japanese Patent Laid-Open No. 2009-49293